CN112534684A

CN112534684A - Concentrated winding layout for AC motor stator

Info

Publication number: CN112534684A
Application number: CN201980054312.1A
Authority: CN
Inventors: R·B·索伦森; H-J·图加德
Original assignee: Siemens Gamesa Renewable Energy AS
Current assignee: Siemens Gamesa Renewable Energy AS
Priority date: 2018-08-21
Filing date: 2019-08-19
Publication date: 2021-03-19
Also published as: EP3614533A1; EP3807979A1; US20210242740A1; WO2020038886A1

Abstract

An AC electric machine (11) comprising: a stator (20) having a plurality of teeth (101, 102, 3, 104, 105, 106, 107, 108, 109, 110, 111, 112) alternating with a plurality of slots (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 2) in a circumferential direction (X); a concentrated winding layout (100) comprising a plurality of coils (201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212) wound on the plurality of teeth (101, 102, 03, 104, 105, 106, 107, 108, 109, 110, 111, 112) and belonging to at least six phases (A1, A2, B1, B2, C1, C2), each slot of the plurality of slots (1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12) accommodating at least two coils of the plurality of coils (201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212), each phase (A1, A2, B1, B2, C1, C2) of the at least six phases comprising a first coil (201, 202, 203, 204, 205, 206) and a second coil (201, 205, 206) wound in an opposite direction with respect to the first coil (202, 203, 204, 206) of the same phase (A1, A2, B1, B2, C1, C2), 208. 209, 210, 211, 212); a plurality of parallel interconnects (301, 302, 303, 304, 305, 306) connecting the first and second coils of each phase.

Description

Concentrated winding layout for AC motor stator

Technical Field

The invention relates to a concentrated winding layout for an AC motor stator. In particular, but not exclusively, the invention may relate to a concentrated winding layout for a stator of a generator of a wind turbine. The invention also relates to a manufacturing method for manufacturing an AC machine comprising a concentrated winding arrangement in a stator of the AC machine.

Background

Designing a multi-phase AC machine with a winding arrangement having two or more coils per slot requires special attention in providing an efficient electrical insulation system.

First, the motor stator magnet windings will be insulated from the stator by an insulating portion, which is commonly referred to as a ground wall or main wall insulation. If the machine is designed for a single layer (i.e., one coil per slot) winding layout, then main wall insulation is sufficient, assuming the magnet wires/strands are turn-to-turn insulated.

If the machine is designed with two (double layer winding layout) or more coils per slot, it may be necessary to add a phase separator within each slot to insulate each phase from each other. The dimensions of the phase separator, in particular the thickness, depend on the maximum voltage difference between the coils belonging to the different phases, which are accommodated in the same tank adjacent to each other and therefore need to be separated by the phase separator.

The above problems are particularly relevant in multi-phase AC machines having more than three phases. For larger electrical machines, such as some generators for offshore wind turbines, the generator windings may be split into two three-phase systems (six-phase AC machines), fed from two independent voltage converters, each generating a three-phase sinusoidal waveform.

The two three-phase systems can generally be arranged in series with one another and electrically separated by a phase angle of 30 ° or 60 ° (any other phase angle shift is possible). Offsetting one of the converter systems to produce an angular difference from the two converter systems provides an opportunity to reduce torque ripple. The method also provides great flexibility in combining winding configurations of the machine to minimize voltage stress.

However, in known multi-phase AC machines with concentrated winding layouts, the voltage difference between the phases accommodated in the same slot is not optimal. The maximum voltage difference may exceed the nominal voltage of the motor. This requires the insertion of a thick phase separator.

Therefore, there remains a need in the art for a multi-phase AC electric machine that reduces or ultimately eliminates the voltage difference between the phases contained in the same slot of the stator, thereby also reducing the thickness of or ultimately eliminating the phase separator.

Smaller phase separators result in higher slot/copper fill factor, thereby reducing winding resistance, which reduces the power dissipation of the entire stator.

Disclosure of Invention

The above needs may be met by the subject matter according to the independent claims. Advantageous embodiments of the invention are described by the dependent claims.

According to a first aspect of the present invention, there is provided an AC electric machine comprising:

a stator having a plurality of teeth alternating with a plurality of slots in a circumferential direction,

a concentrated winding arrangement comprising a plurality of coils wound on the plurality of teeth and belonging to at least six phases, each slot of the plurality of slots accommodating at least two coils of the plurality of coils, each phase of the at least six phases comprising a first coil and a second coil, the second coil of one phase being wound in opposite directions with respect to a respective first coil of the same phase,

a plurality of interconnects connecting the first coil and the second coil of each phase, the interconnects being parallel to each other.

According to a second aspect of the present invention, there is provided a method of manufacturing an AC electric machine, the method comprising:

providing a stator having a plurality of teeth alternating in a circumferential direction with a plurality of slots, arranging a concentrated winding layout comprising a plurality of coils wound on the plurality of teeth and belonging to at least six phases, each slot of the plurality of slots accommodating at least two coils of the plurality of coils, each phase of the at least six phases comprising a first coil and a second coil, the second coils of one phase being wound in opposite directions with respect to the respective first coils of the same phase,

arranging a plurality of interconnects for connecting the first and second coils of each phase, the interconnects being parallel to each other.

In the concentrated winding layout of the present invention, the interconnects all have the same length and any crossover between conductors that make up the winding layout is avoided.

The AC machine of the invention may in particular be a permanent magnet synchronous machine. The electrical machine may be or comprise an electric motor or a generator, in particular a generator comprised in a wind turbine.

According to an embodiment of the invention, each of the plurality of slots extends radially from a slot top to a slot bottom, and each of the interconnecting members extends between the slot top of one slot to the slot bottom of another slot. Each interconnect may extend between two respective slots of a first set of slots alternating in a circumferential direction with a second set of slots that accommodate coils that are not connected by any interconnect.

According to an embodiment of the invention, the concentrated winding layout comprises at least a first and a second set of coils corresponding to a first and a second set of three phases, respectively, of the concentrated winding layout.

In such embodiments, each interconnecting member may extend through six respective teeth and five respective slots.

In such an embodiment, the first set of coils is electrically connected in series to the second set of coils. The first set of coils and the second set of coils may be electrically separated by a phase angle of 30 ° or 60 °.

The invention is also applicable to concentrated winding layouts with more than six phases.

According to an embodiment of the invention, the first set of coils is wound on a respective first set of teeth and the second set of coils is wound on a respective second set of teeth, the second set of teeth alternating with the first set of teeth in the circumferential direction.

In particular, according to an embodiment of the present invention, each of the first set of coils wound on the first set of teeth and each of the second set of coils wound on the second set of teeth may comprise the following arrangement along the circumferential direction:

-a first coil of a first phase,

-a first coil of a second phase,

-a first coil of a third phase,

-a second coil of the first phase connected to the first coil of the first phase by a first interconnect,

-a second coil of the second phase connected to the first coil of the second phase by a second interconnect,

-a second coil of the third phase connected to the first coil of the third phase by a third interconnect.

Each coil of the plurality of coils may be wound on a respective tooth of the plurality of teeth between the phase input or the neutral output and one of the plurality of interconnects.

According to an embodiment of the present invention, in each of the first and second groups of coils, the first coil of the first phase, the first coil of the second phase, and the first coil of the third phase are wound in the same direction. Conversely, the second coil of the first phase, the second coil of the second phase, and the second coil of the third phase may all be wound in an opposite direction with respect to the first coil.

In view of the above, the first and second sets of coils may be wound in opposite directions, i.e., a first coil of the first set of coils is wound in an opposite direction to a first coil of the second set of coils, and a second coil of the first set of coils is wound in an opposite direction to a second coil of the second set of coils.

Embodiments of the present invention will now be described with reference to the accompanying drawings. The invention is not limited to the embodiments shown or described.

Drawings

Fig. 1 shows a schematic cross section of a wind turbine comprising an AC-motor according to the invention;

FIG. 2 shows a schematic diagram of a 6-phase concentrated winding layout according to the present invention;

FIG. 3 shows a voltage vector diagram of the concentrated winding layout of FIG. 2;

figure 4 schematically illustrates the physical arrangement of the concentrated winding layout of figures 2 and 3;

fig. 5 shows a slot of a stator of an AC motor according to the present invention.

Detailed Description

The illustration in the drawings is schematically. It is noted that in different figures, similar or identical elements are provided with the same reference signs.

Fig. 1 shows a wind turbine 1 according to the invention. The wind turbine 1 comprises a tower 2 mounted on a foundation, not shown. The nacelle 3 is arranged on top of the tower 2.

The wind turbine 1 further comprises a wind rotor 5 having at least one blade 4 (in the embodiment of fig. 1, the wind rotor comprises three blades 4, of which only two blades 4 are visible). The wind rotor 5 is rotatable about an axis of rotation Y.

The blades 4 extend substantially radially with respect to the rotation axis Y.

The wind turbine 1 comprises a generator 11 comprising a stator 20 and a rotor 30. The rotor 30 is rotatable relative to the stator 20 about a rotation axis Y.

The wind turbine 5 is rotationally coupled to the generator 11 directly, for example directly driven, or by means of a rotatable main shaft 9 and/or via a gearbox (not shown in fig. 1). A schematically shown bearing assembly 8 is provided to hold the spindle 9 and the rotor 5 in position, the rotatable spindle 9 extending along the axis of rotation Y.

As shown in fig. 4, the stator 20 has a plurality of

teeth

101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112 alternating with a plurality of

slots

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 in a circumferential direction X of the stator 20, oriented circumferentially with respect to the axis of rotation Y.

Each of the plurality of

grooves

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 extends in a radial direction R, i.e. orthogonal to the rotation axis Y, from a

respective groove bottom

1b, 2b, 3b, 4b, 5b, 6b, 7b, 8b, 9b, 10b, l1b, 12b to a respective groove top la, 2a, 3a, 4a, 5a, 6a, 7a, 8a, 9a, 10a, 11a, 12 a.

According to the invention, the generator 11 comprises a concentrated winding layout 100 comprising a plurality of

coils

201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212 wound on a plurality of

teeth

101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112 and belonging to at least six phases Al, a2, B1, B2, C1, C2, each

slot

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 accommodating at least two coils, each phase Al, a2, B1, B2, C1, C2 comprising a

first coil

201, 202, 203, 204, 205, 206 and a

second coil

207, 208, 209, 210, 211, 212, the

second coil

207, 208, 209, 210, 211, 212 of one phase being wound in opposite direction with respect to the respective

first coil

201, 202, 203, 204, 205, 206 of the same phase. The concentrated winding layout 100 further comprises a plurality of

interconnects

301, 302, 303, 304, 305, 306 connecting the first and second coils of each phase, the

interconnects

301, 302, 303, 304, 305, 306 being parallel to each other.

The

coils

201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212 and the

interconnects

301, 302, 303, 304, 305, 306 carry respective insulation on respective surfaces.

Fig. 2 schematically shows, for each phase Al, a2, B1, B2, Cl, C2, a respective

first coil

201, 202, 203, 204, 205, 206 and

second coil

207, 208, 209, 210, 211, 212, as detailed below. Each

interconnection

301, 302, 303, 304, 305, 306 is schematically represented by a dot.

Fig. 3 schematically shows a corresponding voltage vector diagram. The first set of

coils

201, 203, 205, 207, 209, 211 is electrically separated from the second set of

coils

202, 204, 206, 208, 210, 212 by a phase angle α of 30 °.

According to other embodiments of the invention (not shown), the phase angle α may have any other value, for example 60 °.

In the embodiment of fig. 2-4, the concentrated winding layout 100 includes a first set of

coils

201, 203, 205, 207, 209, 211 and a second set of

coils

202, 204, 206, 208, 210, 212 corresponding to the first set of three phases Al, B1, Cl and the second set of three phases a2, B2, C2, respectively. Each of the first set of

coils

201, 203, 205, 207, 209, 211 and the second set of

coils

202, 204, 206, 208, 210, 212 corresponds to a respective three-phase system. The first set of

coils

201, 203, 205, 207, 209, 211 are connected by three

respective interconnects

301, 302, 303. The second set of

coils

202, 204, 206, 208, 210, 212 are connected by three other

respective interconnects

304, 305, 306.

According to other embodiments of the invention (not shown), the concentrated winding arrangement may comprise a different number of phases, for example more than two three-phase systems.

The first set of

coils

201, 203, 205, 207, 209, 211 are electrically connected in series to the second set of

coils

202, 204, 206, 208, 210, 212.

Referring to the illustration of the winding layout 100 in fig. 4, a first set of

coils

201, 203, 205, 207, 209, 211 is wound on a respective first set of

teeth

101, 103, 105, 107, 109, 111, and a second set of

coils

202, 204, 206, 208, 210, 212 is wound on a respective second set of

teeth

102, 104, 106, 108, 110, 112, the second set of teeth alternating in the circumferential direction X with the first set of

teeth

101, 103, 105, 107, 109, 111.

The first set of

coils

201, 203, 205, 207, 209, 211 comprises, along the circumferential direction X:

a first coil 201 of a first phase a1,

a first coil 203 of a second phase B1,

a first coil 205 of a third phase Cl,

a second coil 207 of the first phase Al connected to the first coil 201 of the first phase Al by a first interconnection 301,

a second coil 209 of the second phase B1 connected to the first coil 203 of the second phase B1 by a second interconnect 302,

a second coil 211 of a third phase Cl connected to the first coil 205 of the third phase Cl by a third interconnection 303.

The first coils 201, 203, 205 are wound according to a first direction, while the

second coils

207, 209, 211 are wound according to a second direction opposite to the first direction.

According to an embodiment of the invention, the

first coils

201, 203, 205 are wound clockwise, while the

second coils

207, 209, 211 are wound counter-clockwise.

According to other embodiments of the invention, the

first coils

201, 203, 205 are wound counter clockwise and the

second coils

207, 209, 211 are wound clockwise.

More particularly:

-said first coil 201 of said first phase Al is wound on a first tooth 101 of said first set of

teeth

101, 103, 105, 107, 109, 111 in said first direction;

-the first coil 203 of the second phase B1 is wound on the second tooth 103 of the first set of

teeth

101, 103, 105, 107, 109, 111 in the first direction,

-the first coil 205 of the third phase Cl is wound on a third tooth 105 of the first set of

teeth

101, 103, 105, 107, 109, 111 in the first direction,

-the second coil 207 of the first phase A1 is wound on the fourth tooth 107 of the first set of

teeth

101, 103, 105, 107, 109, 111 in the second direction,

the second coil 209 of the second phase B1 being wound on a fifth tooth 109 of the first set of

teeth

101, 103, 105, 107, 109, 111 in the second direction,

-said second coil 211 of said third phase Cl is wound on a sixth tooth 111 of said first set of

teeth

101, 103, 105, 107, 109, 111 in said second direction.

In fig. 4, the slots 1-12 may be identified as a series of slots oriented from the first slot 1 to the twelfth slot 12 according to the circumferential direction X.

The first set of

coils

201, 203, 205, 207, 209, 211 are connected in

slots

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 such that:

the first coil 201 of the first phase a1 is wound between the input 401 of the first phase Al (at the slot bottom 1b of the first slot 1) and the first interconnection 301 (at the slot top 12a of the twelfth slot 12, the twelfth slot 12 is adjacent to the first slot 1 in the opposite direction with respect to the circumferential direction X);

the first coil 203 of the second phase B1 is wound between the second interconnection 302 at the slot top 2a of the second slot 2 and the neutral output N at the slot bottom 3B of the third slot 3,

the first coil 205 of the third phase Cl is wound between the third interconnection 303 at the slot top 4a of the fourth slot 4 and the input 403 of the third phase Cl at the slot bottom 5b of the fifth slot 5,

the second coil 207 of the first phase Al is wound between the neutral output N at the slot top 7a of the seventh slot 7 and the first interconnection 301 at the slot bottom 6b of the sixth slot 6,

the second coil 209 of the second phase B1 is wound between the input 402 of the second phase B1 at the slot top 9a of the ninth slot 9 and the second interconnection 302 at the slot bottom 8B of the eighth slot 8,

the second coil 211 of the third phase Cl is wound between the neutral output N at the slot top 11a of the eleventh slot 11 and the third interconnection 303 at the slot bottom 10b of the tenth slot 10.

The second set of

coils

202, 204, 206, 208, 210, 212 comprises, along the circumferential direction X:

a first coil 202 of a first phase a2,

a first coil 204 of a second phase B2,

a first coil 206 of a third phase C2,

a second coil 208 of the first phase A2 connected to the first coil 202 of the first phase A2 by a fourth interconnect 304,

a second coil 210 of the second phase B2 connected to the first coil 204 of the second phase B2 by a fifth interconnect 305,

a second coil 212 of the third phase C2 connected to the first coil 206 of the third phase C2 by a sixth interconnection 306.

The first coils 202, 204, 206 are wound according to a second direction, while the

second coils

208, 210, 212 are wound according to a first direction.

More particularly:

-the first coil 202 of the first phase a2 is wound on the first tooth 102 of the second set of

teeth

102, 104, 106, 108, 110, 112 in the second direction;

the first coil 204 of the second phase B2 is wound on the second tooth 104 of the second set of

teeth

102, 104, 106, 108, 110, 112 in the second direction,

-the first coil 206 of the third phase C2 is wound on the third tooth 106 of the second set of

teeth

102, 104, 106, 108, 110, 112 in the second direction,

-the second coil 208 of the first phase A2 is wound on the fourth tooth 108 of the second set of

teeth

102, 104, 106, 108, 110, 112 in the first direction,

the second coil 210 of the second phase B2 being wound on the fifth tooth 110 of the second set of

teeth

102, 104, 106, 108, 110, 112 in the first direction,

the second coil 212 of the third phase C2 is wound on the sixth tooth 112 of the second set of

teeth

102, 104, 106, 108, 110, 112 in the first direction.

The second set of

coils

202, 204, 206, 208, 210, 212 are connected in

slots

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 such that:

the first coil 202 of the first phase a2 is wound between the input 402 of the first phase a2 at the slot bottom 1b of the first slot 1 and the fourth interconnect 304 at the slot top 2a of the second slot 2;

the first coil 204 of the second phase B2 is wound between the fifth interconnection 305 at the slot top 4a of the fourth slot 4 and the neutral output N at the slot bottom 3B of the third slot 3,

the first coil 206 of the third phase C2 is wound between the sixth interconnection 306 at the slot top 6a of the sixth slot 6 and the input 406 of the third phase C2 at the slot bottom 5b of the fifth slot 5,

the second coil 208 of the first phase A2 is wound between the neutral output N at the slot top 7a of the seventh slot 7 and the fourth interconnection 304 at the slot bottom 8b of the eighth slot 8,

the second coil 210 of the second phase B2 is wound between the input 405 of the second phase B2 at the slot top 9a of the ninth slot 9 and the fifth interconnection 305 at the slot bottom 10B of the tenth slot 10,

the second coil 212 of the third phase C2 is wound between a neutral output N at the slot top 11a of the eleventh slot 11 and a sixth interconnection 306 at the slot bottom 12b of the seventh slot 12.

In both the first set of

coils

201, 203, 205, 207, 209, 211 and the second set of

coils

202, 204, 206, 208, 210, 212, each of the

interconnects

301, 302, 303, 304, 305, 306 extends between a

slot top

12a, 2a, 4a, 6a of one

slot

12, 2, 4, 6 and a

slot bottom

6b, 8b, 10b, 12b of another slot 6, 8, 10, 12. This ensures that the

interconnects

301, 302, 303, 304, 305, 306 are parallel to each other and have the same length.

Each of the interconnecting

members

301, 302, 303, 304, 305, 306 extends through six respective teeth and five respective slots, i.e., each of the interconnecting

members

301, 302, 303, 304, 305, 306 connects two slots separated from each other by six respective teeth and five respective slots.

In the winding layout 100 described above, the plurality of

slots

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 may be considered to comprise a first set of

slots

2, 4, 6, 8, 10, 12 and a second set of

slots

1, 3, 5, 7, 9, 11 alternating with the first set of

slots

2, 4, 6, 8, 10, 12 in the circumferential direction X, each of the

interconnections

301, 302, 303, 304, 305, 306 extending between two respective slots of the first set of

slots

2, 4, 6, 8, 10, 12. The second set of

slots

1, 3, 5, 7, 9, 11 accommodate the

inputs

401, 402, 403, 404, 405, 406 and the neutral output N of phases a1, a2, B1, B2, C1, C2.

The winding layout 100 described above may be repeated N times (N being an integer or fraction) upstream of the first tooth 101 of the first set of

teeth

101, 103, 105, 107, 109, 111 or downstream of the twelfth slot 12

"upstream" and "downstream" refer to the circumferential direction X.

Referring to fig. 5, a slot 501 (corresponding to any of

slots

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 of fig. 4) is shown between two

teeth

502 and 503. The slot 501 accommodates two

adjacent phases

504, 505. A wall insulator 506 is disposed between each

phase

504, 505 and the walls of

teeth

502 and 503. Radially oriented phase separators 507 separate the

phases

504, 505 from each other. According to the present invention, the thickness of the phase separator 507 can be minimized due to the reduction of the voltage difference between the

phases

504, 505.

Finally, in accordance with a possible embodiment of the invention, the phase separator 507 is not present in case the voltage difference between the

phases

504, 505 is reduced to a minimum or zero value. In this case, the insulation on the coil surface of each

phase

504, 505 is sufficient to provide effective insulation between the

phases

504, 505.

Claims

1. An AC electric machine (11) comprising:

a stator (20) having a plurality of teeth (101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112) alternating with a plurality of slots (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) in a circumferential direction (X),

a concentrated winding layout (100) comprising a plurality of coils (201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212) wound on the plurality of teeth (101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112) and belonging to at least six phases (Al, A2, B1, B2, Cl, C2), each slot of the plurality of slots (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) accommodating at least two coils of the plurality of coils (201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212), each phase (Al, A2, B1, B2, Cl, C2) of the at least six phases comprising a first coil (201, 202, 203, 204, 205, 206) and a second coil (207, 208, 209, 210), the first coil (201, 202, 203, 204, 205, 206), the second coil (207, 208, 210, 209, 212), the first coil (209, 210, 212), 212) Are wound in opposite directions with respect to respective first coils (201, 202, 203, 204, 205, 206) of the same phase,

a plurality of interconnects (301, 302, 303, 304, 305, 306) connecting the first and second coils of each phase, the interconnects (301, 302, 303, 304, 305, 306) being in parallel with each other.

2. The AC electrical machine (11) of claim 1, wherein each of the plurality of slots (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) extends radially from a slot top (la, 2a, 3a, 4a, 5a, 6a, 7a, 8a, 9a, 10a, 11a, 12 a) to a slot bottom (1 b, 2b, 3b, 4b, 5b, 6b, 7b, 8b, 9b, 10b, 11b, 12 b), each of the interconnects (301, 302, 303, 304, 305, 306) extending between the slot top (12 a, 2a, 4a, 6 a) of one slot (12, 2, 4, 6) and the slot bottom (6 b, 8b, 10b, 12 b) of another slot (6, 8, 10, 12).

3. The AC electric machine (11) of claim 1 or 2, wherein the plurality of slots (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) comprises a first set of slots (2, 4, 6, 8, 10, 12) and a second set of slots (1, 3, 5, 7, 9, 11) alternating with the first set of slots (2, 4, 6, 8, 10, 12) in the circumferential direction (X), each of the interconnects (301, 302, 303, 304, 305, 306) extending between two respective slots of the first set of slots (2, 4, 6, 8, 10, 12).

4. The AC electrical machine (11) of any of the preceding claims, wherein the concentrated winding layout (100) comprises at least a first set of coils (201, 203, 205, 207, 209, 211) and a second set of coils (202, 204, 206, 208, 210, 212) corresponding to a first set of three phases (Al, B1, Cl) and a second set of three phases (a 2, B2, C2) of the concentrated winding layout (100), respectively.

5. The AC electric machine (11) of claim 4, wherein each of the interconnects (301, 302, 303, 304, 305, 306) extends through six respective teeth and five respective slots.

6. The AC electric machine (11) of claim 4 or 5, wherein the first set of coils (201, 203, 205, 207, 209, 211) is electrically connected in series with the second set of coils (202, 204, 206, 208, 210, 212).

7. The AC electric machine (11) of claim 6, wherein the first set of coils (201, 203, 205, 207, 209, 211) and the second set of coils (202, 204, 206, 208, 210, 212) are electrically separated by a phase angle (a) of 30 ° or 60 °.

8. An AC electric machine (11) according to any of claims 4 to 7, wherein the first set of coils (201, 203, 205, 207, 209, 211) is wound on a respective first set of teeth (101, 103, 105, 107, 109, 111) and the second set of coils (202, 204, 206, 208, 210, 212) is wound on a respective second set of teeth (102, 104, 106, 108, 110, 112) which alternate with the first set of teeth (101, 103, 105, 107, 109, 111) in the circumferential direction (X).

9. The AC electric machine (11) of claim 8, wherein each coil of the first set of coils (201, 203, 205, 207, 209, 211) and the second set of coils (202, 204, 206, 208, 210, 212) comprises, along the circumferential direction (X):

-a first coil (201, 202) of a first phase (Al, A2),

-a first coil (203, 204) of a second phase (B1, B2),

-a first coil (205, 206) of a third phase (Cl, C2),

-a second coil (207, 208) of the first phase (Al, A2) connected to the first coil (201, 202) of the first phase (Al, A2) by a first interconnect (301, 304),

-a second coil (209, 210) of the second phase (B1, B2) connected to the first coil (203, 204) of the second phase (B1, B2) by a second interconnect (302, 305),

-a second coil (211, 212) of the third phase (Cl, C2) connected to the first coil (205, 206) of the third phase (Cl, C2) by a third interconnect (303, 306).

10. The AC electrical machine (11) of claim 9, wherein in each of the first set of coils (201, 203, 205, 207, 209, 211) and the second set of coils (202, 204, 206, 208, 210, 212), the first coil (201, 202) of the first phase (Al, a 2), the first coil (203, 204) of a second phase (B1, B2), and the first coil (205, 206) of a third phase (Cl, C2) are wound in the same direction.

11. The AC electrical machine (11) of claim 10, wherein the first coil (201) of the first phase (Al) in the first set of coils (201, 203, 205, 207, 209, 211) is wound in an opposite direction to the first coil (202) of the first phase (a 2) in the second set of coils (202, 204, 206, 208, 210, 212).

12. The AC electric machine (11) of any preceding claim, wherein each of the plurality of coils (201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212) is wound on a respective one of the plurality of teeth (101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112) between a phase input (401, 402, 403, 404, 405, 406) or a neutral output (N) and one of the plurality of interconnects (301, 302, 303, 304, 305, 306).

13. A wind turbine comprising a generator (11) according to any of the preceding claims.

14. A method of manufacturing an AC electric machine (11), comprising:

providing a stator (20) having a plurality of teeth (101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112) alternating in a circumferential direction (X) with a plurality of slots (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12),

arranging a concentrated winding layout (100) comprising a plurality of coils (201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212) wound on the plurality of teeth (101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112) and belonging to at least six phases (Al, A2, B1, B2, Cl, C2), each slot of the plurality of slots (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) accommodating at least two coils of the plurality of coils (201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212), each phase (Al, A2, B1, B2, Cl, C2) of the at least six phases comprising a first coil (201, 202, 203, 204, 205, 206) and a second coil (207, 208, 209, 210), the first coil (201, 202, 203, 204, 205, 206), the first coil (207, 208, 209, 212), the first coil (209, 210) of, 211. 212) are wound in opposite directions with respect to respective first coils (201, 202, 203, 204, 205, 206) of the same phase,

a plurality of interconnects (301, 302, 303, 304, 305, 306) for connecting the first and second coils of each phase are arranged, the interconnects (301, 302, 303, 304, 305, 306) being parallel to each other.

15. The method of the preceding claim, wherein the concentrated winding layout (100) comprises at least a first set of coils (201, 203, 205, 207, 209, 211) and a second set of coils (202, 204, 206, 208, 210, 212) electrically connected in series with the first set of coils (201, 203, 205, 207, 209, 211), the first and second sets of coils corresponding to a first set of three phases (Al, B1, Cl) and a second set of three phases (a 2, B2, C2) of the concentrated winding layout (100), respectively, the first set of coils (201, 203, 205, 207, 209, 211) and the second set of coils (202, 204, 206, 208, 210, 212) being electrically separated by a phase angle (a) of 30 ° or 60 °.